Biomedical subjects

H D Ohlenbusch

Publications and source records attributed to H D Ohlenbusch.

9 recordsLinked to original sources

PubMed1985

Purification and properties of an FAD-containing NADH oxidase from Mycoplasma capricolum.

From the prokaryotic microorganism Mycoplasma capricolum an FAD-containing NADH oxidase has been purified by preparative FPLC to homogeneity, as judged by polyacrylamide gel electrophoresis. The apparent molecular mass of the enzyme was found to be 72.5 kDa, with an isoelectric point of 5.2, and no detectable subunits. No iron, copper, manganese or molybdenium could be detected. On the basis of a minimum molecular mass of 72.5 kDa a ratio of FAD/protein of 1:1 could be derived. Its amino-acid composition, the light absorption and the fluorescence spectra are presented.

Amino Acids↗

PubMed1984

Purification and properties of a manganese-containing superoxide dismutase from Acholeplasma laidlawii.

From the prokaryotic microorganism Acholeplasma laidlawii the major manganese-containing superoxide dismutase has been purified to homogeneity, as judged by polyacrylamide gel electrophoresis. The molecular mass of the enzyme was found to be 41 500 Da. It consists of two subunits of identical size and has an isoelectric point of 6.4. The enzyme contains 0.51 +/- 0.05 atoms of manganese per subunit. Its amino-acid composition and light absorption spectra are presented and compared with Mn- and Fe- containing superoxide dismutases from other prokaryotic organisms.

Acholeplasma laidlawii↗

PubMed1976

Proton-dependent dissociation equilibrium of hemoglobin. 1. A 700-nanometer light-scattering study on horse methemoglobin in the pH range 4.8 to 7.2.

The effect of proton concentration upon the subunit dissociation of horse methemoglobin has been investigated at two ionic strengths by light scattering photometry at 700 nm. Differential refractometry revealed a slight but systematic decrease of the specific refractive index increment with decreasing protein concentration for solutions in dialytic equilibrium with the solvent. In the pH range 4.8-7.2 the dissociation can be described by a simple equilibrium between tetramers and dimers. The dissociation constant Kd of the met derivative is found to be very similar to those of the O2- and CO-ligated states. From the slope of a plot of log Kd vs. pH, the number of protons bound is n = 1.3 +/- 0.1 resulting from an increase in the pK values of two groups upon dissociation. These two groups must be identical because the dissociation is symmetrical.

Animals↗

PubMed1976

Proton-dependent dissociation equilibrium of hemoglobin. 2. Surface pressure measurements in monolayers of horse hemoglobin (III).

The molecular weight of hemoglobin (III) in monolayers on aqueous subsolutions has been determined by measuring the surface pressure as a function of the protein surface concentration. The dissociation equilibrium between tetrameric and dimeric hemoglobin (III) was determined for spread as well as adsorbed monolayers. The results were compared with analogous measurements in solution. It was found that the numerical value and the pH dependence of the dissociation constant were similar both in the bulk and in the surface phase of the solution. From these findings it was concluded that the native conformation of hemoglobin (III) is retained after adsorption at aqueous surface.

Animals↗

PubMed1969